A light-emitting diode (hereinafter, referred to as an LED) is an electronic light source, based on a semiconductor diode. When an LED is forward biased (switched on), electrons are able to recombine with holes, and energy is released in the form of light. This effect is called electroluminescence and the color of the light is determined by the energy gap of materials in the semiconductor.
LEDs provide many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching.
Applications of LEDs are diverse. For instance, they may be used as a low-energy replacement for traditional light sources in well-established applications such as lighting, indicators and automotive lighting. The compact size of LEDs has allowed new text, video displays and sensors to be developed, while their high switching rates are useful in communication technology.
LEDs may also be used to produce high intensity white light. There are two ways of producing white light using LEDs. One way is to use individual LEDs that emit three primary colors—red, green and blue, and then mix all the colors to produce white light. The other way is to use phosphors to convert monochromatic light from LEDs to broad-spectrum white light.